Field of the Invention
Example embodiments relate generally to cooling electronic devices, and more particularly to a method and apparatus for a variable heat conductor positionable between an electronic device and a heat sink to facilitate rapid warming of the electronic device during startup of the electronic device at low temperatures.
Related Art
Electronic devices, such as integrated circuits, processors, memory chips, field-programmable gate arrays (FPGA), logic chips, etc., generally require cooling in order to operate efficiently and effectively, especially at high temperatures. In order to facilitate such cooling, a conventional thermal stack-up 10 is often employed, as shown for instance in FIG. 1. The thermal stack-up 10 may include a heat conductor 4 in contact with an electronic device 2 and a heat sink 6. The heat conductor 4 is generally made from a material, such as a metal, that offers a high heat conductivity in order to efficiently conduct and transmit heat from the electronic device 2 to the heat sink 6. In particular, the heat conductor 4 absorbs thermal energy from the electronic device 2 via convection, radiation, and mostly notably conduction, and facilitates the transfer of this energy to the heat sink 6. Because conduction is the primary mode of the thermal energy transmission, the heat conductor 4 often directly contacts both the electronic device 2 and the heat sink 6.
The heat sink 6 often times takes the form of an enclosure, a cooling plate, a housing, a support, fins, ribs, or any other suitable structure that facilitates heat expulsion from the heat conductor 4.
Conventionally, a thermal stack-up 10 is effective in removing thermal heat from an electronic device 2, allowing the electronic device 2 to operate in an appropriate temperature operating range even at high ambient temperatures (or, even in confided spaces, where operation of the electronic device 2 may cause significant heat emission). However, while a conventional thermal stack-up 10 is effective in removing heat, this heat removal can be counterproductive during periods of electronic device 2 startup, especially when the startup occurs at low temperatures. The startup of ever more highly-integrated circuits, with services required to operate in wide temperature ranges (for instance, in temperature ranges between −40° C. and 85° C.), act to exacerbate startups at very low temperatures. For instance, conventional high-performance central processing units (CPUs) currently are not rated to be able to quickly turn-on at −40° C. Therefore, at very low temperatures, electronic devices 2 in a conventional thermal stack-up 10 may either take an exceptionally long period of time to startup, or the electronic devices 2 may not be able to turn-on and function, at all.